CaO对MgO-Al2O3-SiO2系微晶玻璃结构与性能的影响

以化学纯试剂为原料,采用熔融法制备MgO-Al2O3-SiO2(MAS)系微晶玻璃.利用DSC、XRD、SEM等及理化性能测试手段研究了不同CaO含量对微晶玻璃析晶行为、物相组成、显微结构及理化性能的影响.结果表明:一定含量的CaO可以降低析晶活化能,促进玻璃析晶;随CaO含量的增加,微晶玻璃主晶相由假蓝宝石向α-堇青石转变,晶体形貌由棒状晶转变为枝状晶,晶粒尺寸呈先减后增的趋势;当CaO含量为3wt;时微晶玻璃热膨胀系数和相对介电常数(εr)达到最低,分别为3.89×10-1℃-1和10.09(1 MHz);当不外添CaO时微晶玻璃Vickers硬度达到最大,为10.52 GPa.

Effect of CaO on Structure and Properties of MgO-Al2O3-SiO2 System Glass Ceramics

MgO-Al2O3-SiO2 (MAS)-based glass ceramics were prepared by melting method with pure chemical reagents.The effects of CaO content on crystallization behavior、phase composition、microstructure、physical and chemical properties of glass ceramics were investigated by DSC,XRD,SEM,and performance testing methods.The results show that a certain content of CaO could reduce the activation energy of crystallization,which as a result can promote the glass crystallization;On the other hand,with the increase of CaO,the main crystal phase transfers from sapphirine to α-cordierite,crystal morphology from rod like crystal into dendrite,the grain size decreases at first and then increases;with the addition of 3wt; CaO,the thermal expansion coefficient and the relative dielectric (εr) of glass ceramics show the lowest value,are 3.89 × 10-6℃-1 and 10.09 (1 MHz),respectively;the Vickershardness of samples reach the maximum when no CaO is added,is 10.52 GPa.